1. Field of the Invention
The present invention generally relates to guidance devices and more particularly to angular rotation guidance devices for surgical instruments.
2. Discussion of the Related Art
Guidewires and catheters are used in a variety of different medical procedures, for example, during angiographic, endovascular, or other surgical procedures. Guidewires are typically used to position catheters in a body lumen, for example arteries, veins or natural orifices within a mammal. The leading end portion (distal end) of the guidewire is typically introduced into the body through an incision or natural orifice and then advanced to the treatment area. To reach the treatment area, the guidewire may have to be steered into lumens bifurcating from the body lumen. To ensure the guide wire moves into the desired lumen, the distal end of the wire is bent at an angle or into a “J” shape, and the trailing (proximal) end of the wire outside the body is rotated to position the guide wires distal end into the correct lumen to reach the treatment area.
Typically, this is accomplished under x-ray guidance as the distal segment of the guidewire is visible. For example, a radiopaque marker is on the device and under x-ray and/or contrast various aspects and locations of the device may be visualized. Similarly, many catheters have shaped distal ends to allow them to be rotated and steered to various locations in the body. Some catheters are meant to be used over a guidewire and have distal ends which are mounted eccentric to the guidewire. These catheters are rotated from the proximal end to move the eccentric distal tip to one side of the body lumen to deliver treatment.
Advancing and steering surgical instruments in the body under fluoroscopic guidance can be rather difficult as the visual image provided is 2-dimensional and the body lumen anatomy and surgical instrument are working in 3 dimensions. For example, when a J-tipped guidewire is rotated in a lumen, the direction and angular orientation of the J-tip is easily seen when the plane of the “J” is perpendicular to the vector defined by the line of the x-ray source to the patient. As the wire is rotated away from this perpendicular plane, it becomes difficult to determine where the J-tip is pointed. When the plane of the “J” is parallel to the source vector, the “J” shape appears as a single line on the x-ray screen, and it is difficult, if not impossible to discern if the “J” is pointed toward or away from the x-ray source. If the plane of the “J” is at 45 degrees or 135 degrees to the source vector, it will appear as the same image on the x-ray screen. Difficulty in determining the angular orientation of the distal end of the surgical instrument may lead to extended procedure times, suboptimal treatment, and in extreme cases, complications and/or failed treatment.
Therefore, a device and method for determining the angular orientation of surgical instruments within the body is desired.